Non-pharmacological interventions on cognitive functions in mild cognitive impairment and their efficacy in the light of meta-analyses and systematic reviews

Recent decades have witnessed a growing interest in the possibilities of non-pharmacological modulation of cognitive functions in older patients using cognitive interventions, such as cognitive training, cognitive stimulation and cognitive rehabilitation. These approaches are of particular importance in the group of patients with mild cognitive impairment. Since the increased risk of dementia coincides with the possibility of improving cognitive functioning, mild cognitive impairment is considered a condition potentially prone to intervention. The paper presents a systematic literature review of papers that synthesise the results of research on the efficacy of cognitive interventions in patients with mild cognitive impairment. We included 14 out of 136 publications in the review: 4 meta-analyses and 10 systematic reviews, which yielded a total number of 76 studies. The literature analysis led us to conclude that there seems to be clear evidence indicating beneficial, though modest, effects of cognitive training on cognitive functioning, memory in particular. Although the conclusions are less clear in the case of cognitive rehabilitation, they suggest improved behavioural indicators. Studies on the efficacy of cognitive stimulation in mild cognitive impairment are virtually missing in meta-analyses and systematic reviews. At the same time, authors of most of the analysed papers express some methodological reservations regarding these studies. Furthermore, the used interventions and diagnostic criteria are very heterogeneous, which makes the synthesis difficult. As a result of the current quality of evidence for the efficacy of cognitive interventions in patients with mild cognitive impairment, these interventions are assigned not more than the lowest clinical recommendation level. However, in the light of possible improvement of research methodology and the lack of recommendations for any of the available pharmacological therapies for mild cognitive impairment, cognitive interventions remain a promising approach.